A conventional electrical connecting apparatus of this type comprises: a circuit board having, for example, a printed circuit board (PCB); and a probe board disposed at a distance from the underside of the circuit board and provided with a plurality of probes on the underside opposing the surface which faces the circuit board (see, e.g., Patent Document 1). Between the circuit board and the probe board, there is placed an interposer including an elastic connector such as a pogo pin assembly, and through the interposer, each probe of the probe board is electrically connected to a socket provided on the circuit board. The electrical connecting apparatus is connected to a tester body by the socket. On the upside of the above-mentioned circuit board is provided a reinforcing plate for restraining warping of the circuit board. These reinforcing plate, circuit board, interposer and probe board are combined integrally by tightening screw members such as bolts to be inserted from the reinforcing plate side.
More specifically, the front end of a bolt inserted from the upside of the reinforcing plate is screwed into an anchor portion provided on the probe board and tightened. A cylindrical spacer member is mounted on each bolt. The spacer member has its one end brought into contact with the underside of the reinforcing plate and its lower end brought into contact with the top of the anchor portion. When the bolt is tightened, the spacer member keeps the distance from the underside of the reinforcing plate to the tip of each probe approximately constant in cooperation with the anchor portion into which the front end of the bolt is screwed. Thus, unless any deformation in the thickness direction such as warping or wave-like deformation is introduced to the probe board where the probes are provided, the probe tips can be held on an imaginary plane.
However, a deformation in the thickness direction is generally introduced to the probe board, and it is hard to correct this deformation sufficiently by the spacer member. This sometimes causes difference in height of the positions of the probe tips with the deformation of the probe board.
Thus, the applicant of this application proposed to form each probe on the probe board in International Application No. PCT/JP2005/009812 and International Application No. PCT/JP2005/019850 to place each probe so that the tip of the probe may be positioned on an imaginary plane with the deformation of the probe board held as it is. In the PCT/JP2005/009812, it was proposed to change the height of the respective anchor portions according to the deformation of the probe board so that the top surfaces of the respective anchor portions are located on the same plane in order to maintain the deformation of the probe board, thereby aligning the tips of the probes on the same plane. Also, in the foregoing PCT/JP2005/019850, in order to maintain the deformation of the probe board, the spacer members having different lengths according to the deformation of the probe board are applied, thereby aligning the probe tips on an imaginary plane.
Thus, by selecting the height dimension of the anchor portion according to the deformation of the probe board, or by selecting the length dimension of the spacer member whose one end contacts the anchor portion, it is possible to locate the respective tips substantially on the same plane in spite of the deformation of the probe board. Thereby, in spite of the above-mentioned deformation of the probe board, in an electrical test of the tester with a plurality of IC circuits incorporated on a semiconductor wafer, it is possible to make the tips of the respective probes contact the corresponding electrodes with substantially uniform pressing force.
Patent Document 1: International Publication No. 2005/106504